• Membrane and Water Treatment
• /
• v.1 no.1
• /
• pp.1-12
• /
• 2010

Membrane distillation process was used for purification of pre-treated natural water (tap water). The rejection of inorganic and organic compounds in this process was investigated. The obtained rejection of inorganic solutes was closed to 100%, but the volatile organic compounds (VOCs) diffused through the membrane together with water vapour. The content of trihalomethanes (THMs) in the obtained distillate was two-three fold higher than that in the feed, therefore, the rejection of the total organic compounds present in the tap water was reduced to a level of 98%. The intensive membranes scaling was observed during the water separation. The morphology and composition of the fouling layer was studied using scanning electron microscopy coupled with energy dispersion spectrometry. The influence of thermal water pre-treatment performed in a heat exchanger followed by filtration on the MD process effectiveness was evaluated. This procedure caused that significantly smaller amounts of $CaCO_3$ crystallites were deposited on the membrane surface, and a high permeate flux was maintained over a period of 160 h.

• Proceedings of the Membrane Society of Korea Conference
• /
• 1994.10a
• /
• pp.62-63
• /
• 1994

The membrane technology is more convenient and economical way in the separation field than conventional technology such as distillation, extration, crystallization, and so on. Therefore, membrane are used as efficient tools for the separation and concentration of molecular mixture in many industrial area. Although the polymeric membrane have various advantage, they have disadvantages as well. One of them is a poor resistance to organic solvent. Therefore, organic solvent resistant membranes were prepared by soluble polyimide. prepared by phase inversion method. The membranes were The homogeneous polymer solutions were obtained by the two different method ; the one is that the polymer sythesized was completely dissolved in a solvent to prepare a membrane casting solution, the other is that a membrane casting solution was prepared by the unit process from the viscose solution of polymerization.

• Journal of Korean Society of Water and Wastewater
• /
• v.19 no.6
• /
• pp.775-780
• /
• 2005

This study was performed to investigate the effect of foulant characteristics on Membrane fouling index such as Silt Density Index (SDI) and Modified Fouling Index (MFI). A linear relationship was found relating the fouling index (both SDI and MFI) on particle concentration, but fouling index values were nonlinearly (exponentially) with increasing organic concentration. When organic matter was the primary cause of fouling, the MFI was not accurately predicted due to internal fouling such as pore adsorption. The fouling index was determined mainly by particle characteristics when both particle and organic coexisted in the feed water. This observation was attributed to lessening of organic pore adsorption by particle cake layer formed on the membrane surface. Bench-scale actual fouling experiments demonstrated that permeate flux declines much faster with feed water containing particles than organic matters although fouling potential predicted by SDI values were identical, indicating that the accurate prediction of fouling potential requires the development of fouling index reflecting different foulant characteristics.

• Proceedings of the Membrane Society of Korea Conference
• /
• 2003.07a
• /
• pp.69-72
• /
• 2003

Volatile organic compounds (VOC) cause air pollution problem and deterioration of atmosphere of petrochemical and fine chemical plants. Hybrid process of membrane and cold-condensation were developed and it effectively removed and recycled the VOC. Operation parameters of the process were optimized to attain hish removal and recycle of VOC. Composite membranes for organic vapor separation were developed in this work by PDMS coating and plasma polymerization on polypropylene and polysulfone support membranes. PDMS and various silicone monomers were tested for several organic vapors such as benzene, toluene, TCE, and HCFC, which are produced in petrochemical and fine chemical industry and causes air pollution problems if are released to atmosphere. Composite membranes prepared in this work showed appreciable performance in terms of organic vapor removal and reuse. Performance variation of the membranes was correlated with their surface characteristics.

• Proceedings of the Membrane Society of Korea Conference
• /
• 2001.04a
• /
• pp.41-47
• /
• 2001

• Membrane Journal
• /
• v.27 no.6
• /
• pp.506-510
• /
• 2017

The interfacial polymerization method has been applied to various fields as a reaction in which reactive monomers dissolved in two immiscible solutions cause polymerization at the interface. In the case of water treatment membranes, m-phenylene diamine and trimesoyl chloride are used as reactants. The performance of the membrane is affected by various polymerization factors. In this study, we investigated how the spreading rate of the organic solution influences the surface and structure of the membrane. Spreading rate of organic solutions was adjusted to 7.6 and 25 mm/sec. The solution volume of the organic phase was adjusted to 1~3 drops. The observed results showed that cracks were not found in the polyamide membrane when dropping at a drop of 7.6 mm/sec and dropping two drops at 25 mm/sec. On the other hand, cracks occurred in all cases. Therefore, the spreading rate of the initial organic solvent is expected to greatly affect the performance of the polyamide membrane.

• Journal of Environmental Science International
• /
• v.20 no.9
• /
• pp.1079-1085
• /
• 2011

The purpose of this study is to find the operational characteristics of nitrifier-dominated membrane bioreactor (MBR), which has been extensively studied for organic removal, especially in terms of nitrite ($NO_2$-N) build-up and membrane fouling. Membrane fouling is one of the important factor which determines the economics of MBR system. The characteristics of membrane fouling was monitored in terms of the fouling indices such as sludge volume index (SVI), the concentration of total organic carbon (TOC) and extracellular polymeric substances (EPS) in a membrane permeate or sludge extract, the absorbance of supernatant at 260 nm. Most of index values except for protein concentration in EPS had a close relation with the increase of suction pressure and SVI value. Nitrifying MBR was superior to the conventional organic-oxidizing MBR in terms of membrane fouling since the fouling index value of nitrifying MBR was lower than that of BOD-oxidizing MBR.

• Membrane and Water Treatment
• /
• v.1 no.3
• /
• pp.193-206
• /
• 2010

Organic fouling and biofouling pose a significant challenge to the membrane filtration process. Photocatalysis-membrane hybrid system is a novel idea for reducing these membranes fouling however, when $TiO_2 photocatalyst nanoparticles are used in suspension, catalyst recovery is not only imposes an extra step on the process but also significantly contributes to increased membrane resistance and reduced permeate flux. In this study, $TiO_2$ photocatalyst has been immobilized by coating on the microfiltration (MF) membrane surface to minimize organic and microbial fouling. Nano-sized $TiO_2$ was first synthesized by a sol-gel method. The synthesized $TiO_2$ was coated on a Poly Vinyl Difluoride (PVDF) membrane (MF) surface using spray coating and dip coating techniques to obtain hybrid functional composite membrane. The characteristics of the synthesized photocatalyst and a functional composite membrane were studied using numerous instruments in terms of physical, chemical and electrical properties. In comparison to the clean PVDF membrane, the $TiO_2$ coated MF membrane was found more effective in removing methylene blue (20%) and E-coli (99%).

• Journal of Korean Society on Water Environment
• /
• v.20 no.2
• /
• pp.183-189
• /
• 2004

The performance of a membrane-coupled anaerobic fermenter system for the recovery of volatile fatty acids (VFAs) from liquid organic sludge was experimentally investigated. Permeation flux was stably kept around $0.2(m^3/m^2/day)$ during operational period. The membrane-coupled fermenter showed 2.2 times higher VFAs concentration and higher VFAs forming rate than those of fermenter without membrane. The fermenter with membrane proved to be an effective system for the recovery of soluble organic materials from liquid sludge.

• Proceedings of the Membrane Society of Korea Conference
• /
• 2004.05a
• /
• pp.90-93
• /
• 2004

In this study, we have reported an organic-inorganic hybrid membrane, which exhibits an asymmetric structure consisted of a carbonized skin layer and a polyimide porous substructure, to synthesize a novel gas separation membrane combining high gas permeability and selectivity. Both the gas permeability and selectivity of the carbonized layer significantly enhanced when compared with those determined in the control polyimide.